The hypothesis of the study is that the speed of absorption of dietary amino acids by gut varies according to the type of protein ingested. The amino-acids appearance rate in the systemic circulation from casein will be slower and more prolonged than those from whey protein, and that the rate of absorption of dietary amino acid will affect post-prandial protein synthesis and muscle protein breakdown differentially with whey proteins stimulating protein synthesis and muscle protein breakdown differentially with whey proteins stimulating protein synthesis and casein inhibiting protein breakdown. The specific aims of the study are to determine rate of absorption of two milk proteins, casein and whey, when administered together as during ingestion of milk, and to determine the effect of rate of absorption of whey and casein on whole body amino-acid kinetics, muscle protein synthesis and breakdown, and synthesis rates of albumin and fibrinogen.